1. Field of the Invention
The present invention relates to a drive for an optical information recording medium which radiates a light beam to the optical information recording medium to record or reproduce information.
The medium used in the present invention is generally called an optical disk or a magneto-optical disk. In this type of disk, a light beam is radiated to the medium and a magnetic field may be directly applied thereto as required to record, reproduce or erase information. Such an optical information recording medium includes a read-only type, write-once type, over-write type and phase change type. The shape of the medium includes a disk shape and a card shape.
2. Related Background Art
FIG. 2 shows a sectional view of a prior art drive (optical disk drive) for an optical information recording medium.
A body 1 has a front panel having a cooling air inlet port 11 and a medium insertion port 2a, and a fan 10. An openable door 3 is attached to the medium insertion port 2a.
A loading mechanism (not shown) for loading an optical disk 9 to a predetermined position, a spindle motor 6 for driving the optical disk 9 and an optical head 7 which radiates a light beam to the optical disk 9 and is movable radially of the optical disk 9 are mounted in the body 1. The spindle motor 6 and the optical head 7 are mounted on a mount table 12.
An operation to load the optical disk 9 into the body 1 of the optical disk drive will now be explained.
A cartridge (not shown) which accommodates the optical disk 9 therein is pushed to the openable door 3 through the medium insertion port 2a formed in the front panel 2 which is a console panel of the optical disk drive.
The door 3 is pivotable in a direction S by a pushing force of the cartridge. Thus, the cartridge causes the door 3 to pivot in the direction S and is fed into the body 1 through the medium insertion port 2a.
In other than the loading mode or unloading to load or unload the cartridge, the door 3 is urged to the front panel 2 by a resilient member (not shown) to close the medium insertion port 2a or the door 3 closes the opening of the medium insertion port 2a by contacting the cartridge.
The optical disk 9 accommodated in the cartridge is guided to a predetermined position on the spindle motor 6 by the loading mechanism. In this manner, the optical disk drive is ready to operate.
In the unloading mode of the optical disk 9, the loading mechanism also unloads the cartridge from the medium insertion port 2a by the reverse operation to that in the loading of the optical disk 9. In the unloading mode of the cartridge, the door 3 is pivoted in the direction S by a mechanism (not shown) in association with the unloading of the cartridge.
When information is to be recorded on the optical disk 9, the spindle motor 6 is driven to rotate the optical disk 9. The optical head 7 is moved to a predetermined position relative to the optical disk 9 and a light beam is radiated in accordance with the information to be recorded.
Various components of the optical disk drive are mounted in the drive. Among them, an electrical circuit board 5 which mounts an electrical circuit is included. The electrical circuit board is a typical example of a heat source which generates a large amount of heat as the drive is operated. The heat source includes other components than the electrical circuit board. Because of such heat source, the temperature in the drive rises during the operation of the drive and the electrical circuit may be broken thereby.
Thus, as cooling means for the heat source, the cooling air inlet port 11 is provided in the front panel 2 and the fan 10 is provided in a rear side of the body 1. Cooling air is taken in from the cooling air inlet port 11 to cool the heat source such as the electrical circuit board 5 and the air used to cool the heat source is ejected from the body 1 by the fan 10. The fan 10 is driven by drive means such as a motor (not shown).
The mount table is fixed to the body 1 by shock absorbing rubber buffering member 13. It is preferable to use a shock absorber such as rubber to fix the mount table 12 to the body 1, in order to prevent vibration externally imparted to the body 1 from being propagated to the mount table 12. If the vibration is propagated to the mount table 12, the vibration is also propagated to the optical head 7, the spindle motor 6 on the mount table 12 and the optical disk 9. This adversely affects the tracking and focusing operations and disturbs the recording and reproducing operation for the optical disk 9.
As described above, in the optical disk drive, the cooling air taken in from the cooling air inlet port 11 not only moves toward the electrical circuit board 5 but also moves toward the optical disk 9 and the optical head 7. As a result, dust contained in the cooling air is deposited on the optical disk 9 and an objective lens of the optical head 7. The same is true for dust entered from gaps of the body. The longer the drive is operated, the more the amount of cooling air taken in the drive increases and the more the amount of deposition of dust increases.
Further, dust deposited on the shock absorbing rubber 13 may float into the disk as the shock absorbing rubber 13 is moved by vibration.
As a result, during the operation of the drive, a tracking error may take place by the influence of the dust, or a portion of the optical disk 9 which is irradiated by the light beam through the objective lens may not rise to a predetermined temperature. Consequently, the writing or reading of data to or from the optical disk 9 is not attained.
In order to solve the problem caused by dust, a proposal has been made to construct the body of the drive to be sealed when the door of the optical disk insertion port is closed. This method prevents the entry of the dust but does not permit taking in external air to cool the heat source. As a result, the heat source such as the electrical circuit board is not sufficiently cooled and the temperature in the drive rises by the heat generated by the heat source, and the electrical circuit board or the optical disk may be damaged.
It has also been proposed to use a sealable member to fix the mount table 12 to seal the gaps between the optical head 7 and the optical disk 9, and the heat source. In this method, however, external vibration is propagated to the optical head 7 and the optical disk 9 and the problem described above is encountered.